Combustion-arc process



March l, 1932. A. E. GREENE 5 COMBUS'TION ARC PROCESS Filed July 8. 1926 W/M///fl//W// 50. f 8 i Y//////////// o 5 & a a,

Patented Mar, 1, 1932 UNITED STATES .ALBERT E. GBEENE, OF MEDINA, 'WASEIN'GTON COMBUSTION-ARC IROCESS v Applibation filed July 8, 1926. Serial No. 121,137.

This invention relates to metallurgy and has 'for anobject the provison of an improved method of reducing ores. More particularly, the invention contemplates the pro- 5 vision of an improved method of Operating a metallurgical furnace provided with' one or more arcing electrodes.

The present application is-a continuation in part of my coending application Serial No. 254224, filed eptembe18, 1918.

According to the method of the invention a mixture of air or other combustion supporting gas and carbonaceous material 'is passed into a furnace chamber along' an electric are to form a combined electric are and combustion flame. The relative amouits of air or other combustion supporting gas and carbonaceous material employed are so 'proportioned that a reducng flame is produced.

Ore to be reduced, such, for example, as iron oxide ore, is charged into the 'furnace chamber through the reducing flame. The ore in passing' through the flame is reduced and the resulting metal is collected on the hearth' of the furnace chamber.

According to the preferred practice, the carbonaceous material and combustion supporting gas are introduced into the combustion zone in such a manner that the resulting combustion flame completely surrounds the are; The ore may be passed through the reducing flame in any suitable manner. The ore, carbonaceous material, and combustion supporting gas maybe introduced into the combustion chamber through separate inlet openings, or any two or all may be introduced through a single inlet or a plurality of similar inlets. Thus, for example, the ore and carbonaceous material may be introduced as a mixture, and the combustion supporting gas may be introduced separately or used for forcing the mixture into the combustion zone. Likewse, the combustion supporting gas maybe used for forcing either the carbonaceous material or the ore into the combustion zone.

The ore is preferably employed 'in a finely divided -condition to promote rapid reduc- "ber. The method of the invention may be ,carred out in conjunction with any other tion. Any suitable carbonaceous material I complished during the course of the passage through 'the -flame, and reduction may be completed on the hearth of the furnace chamsuitable type of metallurgical process. The invention will be better understood from a conideration of the following description in con unction with the acco'mpanying drawings in which Fig. 1 is a sectional elevation of a metallurgical furnace which may be employed in carying out the method ofthe invention; an

Fig. 2 is a sectional plan taken substantially along line A--B of Fig. 1.

The furnace shown in the drawings comprises a horizontal-smoking chamber 6 rovided with a hearth 7 and a roof 8 and a ving-a vertical combustion-are chamber 2 and a horizontal combustion-are chamber 10 communicating with the interior thereof.

The vertical combustion-are chamber is provided with a substantially centrally disposed vertically extending electrodel 'enter- ;ing the chamber through a suitable opening in itsroof. The electrode is mounted for vertical adjustment and connected to a suitable supply of electric current (not shown). An electrode 5 in the bottom of the hearth 7' of the horizontal smelting'chamber provides a terminal for an arc extending downwardly from the electrode 1 in the combustion-are chamber 2.

The horizontal combustion-are chamber 10 is provided with a substantially centrally disposed electrode 11 entering the chamber through a suitable opening in its end wall and connected to a suitable ,source of supply of el'ectric 'current (not shown). The electrode 5 also provides a terminal for an arc extending inwardly from theelectrode 11 in the horizontal combustion-are chamber 10.

The vertical combustion-are clamber 2 is 100 provided at its upper end with means for introducing solid materials such, for example, as powdered coal, ore and fluxing materials,

comprising a conduit 12 extending through an opening in the sidewall 3 of the chamber and communicating with a screw conveyor 15. The horizontal combustion-are chamber is provided with a similar charging conduit and screw conveyor adjacent its outer end. -A gas conduit 14 connected to a suitable source of supply of gas (not shown) commul chamber.

chamber is provided with similar gas conduits or inlets indicated by thenumerals 19,

'g 20 and 21.

A conduit 22 entering the upper portion of the vertical combustion-are chamber provides additional means for introducing solid materials such as powdered coal, ore and fluxing materials.

The horizontal' smelting 'chamber is provided with doors Sa, 8?) and 80 in its side walls whichpermit access to the interior of the -chamber and which provide for the admission of air to burn combustible gases within the chamber. Gas exits are provided at 1 in the vertical combustion-are chamber and at 9 at one end of the horizontal smelting chamber.

A tapping spout -7a is provided for removi ing molten material from the interier of the ing in the introduction of the solid materials lymixedn horizontal smelting chamber.

In the operation of the furnaceshown in the drawings, the combustion-are chambers may be operated separately or in conjunction with one another. That is, either combustionarc chamber may be employed alone or both ma 'be employed at the same time.

n reducing iron oxide ore, th'e ore in finely divided 'condition and mixed with suitable fluxing materials and an amount of powdered coal in excess 'of that required to reduce the ore may be introduced into the vertical combustion-arc chamber by means of the screw c onveyor 15 and the charging conduit 12. Air or other oxidizing gas may be introduced through the conduit 14 for the purpose of aidand/or for the purpose of the coal. i

Additional air or other combustion supporting gas may be adinitted through the in- .lets 13, 16, 17 and 18 provided'for that purpose. v

The combustion supporting gas, ore, powof burning a portion the mixture in passing downwardly sur- The metal and slag resulting from the r`eduction of the iron oxide and fluxng and melting of` the gangue materials are collected' upon the hearth of the horizontal smelting chamber Slag and metal layers on the hearth of the horizontal smelting chambers are indicated at la and a, respectively.

K The above procedure may bemodified in various ways. For example, a strongly reducing flame surrounding the arc may be first established by admitting, in suitable relative amounts, powdered coal through thecharging inlet 12 and air through any orall of the inlet openings provided for that purpose. Ore, preferably in finely divided form, may then be introduced through the charging conduit 22 and permitted to pass downwardly through the 'reducing flame. The ore, in passing through the flame will be reduced, and the resulting metal and slag will collect on the hearth of the horizontal smelting chamber. v

The operation may be so controlled that all of the ore introduced will be reduced in passing through the reducing flame, or the control may be such that only partial reduction is eflected while the ore is passing through the reducing flame and reduction is completed on the hearth of' the horizontal smelting chamber. Air may be admitted through the doors in the side walls of the horizontal smelting chamber to burn excess carbonaceous material within the chamber.

In carrying out the method of the invention either direct current, or alternating single' phase or polyphase current may be employed.

The invention provides a simple andeflicient method for reducing ores. The intense heat and strongly reducing nature of the combustion-arc flame result in rapid reduction of the ore. The operation is extremely simple and easily controllable.

What I claim is:

f 1: The method of Operating furnace which comprises passing a mxture of air and carbonaceous material into the furnace chamber along an electric arc to form a combined electric arc and combustion flame, the relative proportions of air and carbonaceous material being such that a reducing flame is produced, and chargin finely didered coal and fluxing material are intimate-` vided ore into the furnace cham er through the combustion-are chamber and the resulting flame. I

2. The method of Operating a metallurgical furnace which comprises passing a mixture of air and powdered coal into the furnace chamber along an electrc arc to form a combined electric arc and combustion-flame, the relative proportions of powdered coal and air being such that a reducing flame is produced, and charging finely-divided ore into the furnace chamber through the resulting flame.

3. The method of Operating a. metallurgical furnace which comprises passing a mixture of air and carbonaceous material into the furnace chamber along an electric arc to form a combined electrc are and combustion flame,'

the relative proportions of air and carbonaceous material being such that a reducing flame is produced, and charging finely divided iron ore into the furnace chamber through the resulting flame.

2 4. The method of Operating a metallurgia'l furnace which comprises passing a mixture of air. and powdered coal into the furnace chamber along .an electric are to form a combined electric arc and combustion flame, the

2 relative proportions of air and powdered coal being such that a reducing flame is produced, and charging finely divided iron ore into the furnace chamber through the resulting flame.

In witness whereof, I have hereunto subscribed my name this 2nd day 'of July, 1926. w ALBERT E. *GREEN E. 

